CVE-2023-21392
📋 TL;DR
This CVE describes a use-after-free vulnerability in Android's Bluetooth stack that allows local privilege escalation without user interaction. An attacker could exploit this by connecting to a vulnerable device via Bluetooth to corrupt memory and gain elevated privileges. This affects Android devices with vulnerable Bluetooth implementations.
💻 Affected Systems
- Android devices with vulnerable Bluetooth stack
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Full device compromise with attacker gaining root/system-level privileges, potentially installing persistent malware or accessing sensitive data.
Likely Case
Local privilege escalation allowing attacker to bypass app sandboxing, access other apps' data, or perform unauthorized system operations.
If Mitigated
Limited impact if Bluetooth is disabled or device is not discoverable/pairable, though physical proximity risk remains.
🎯 Exploit Status
Exploitation requires Bluetooth proximity and knowledge of the vulnerability, but no authentication or user interaction is needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android 14 (October 2023 security update or later)
Vendor Advisory: https://source.android.com/docs/security/bulletin/android-14
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > System update. 2. Install Android 14 October 2023 security update or later. 3. Restart device after installation.
🔧 Temporary Workarounds
Disable Bluetooth
androidTurn off Bluetooth completely to prevent exploitation
adb shell settings put global bluetooth_on 0
Or manually disable in Settings > Connected devices > Connection preferences > Bluetooth
Restrict Bluetooth visibility
androidMake device non-discoverable and disable auto-pairing
adb shell settings put global bluetooth_discoverability_timeout 0
Or manually set in Bluetooth settings
🧯 If You Can't Patch
- Disable Bluetooth when not in use, especially in public or untrusted environments
- Implement physical security controls to limit Bluetooth proximity to untrusted devices
🔍 How to Verify
Check if Vulnerable:
Check Android version: Settings > About phone > Android version. If below Android 14 October 2023 security patch, device is vulnerable.Check Version:
adb shell getprop ro.build.version.release && adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify Android version is 14 with October 2023 or later security patch level in Settings > About phone > Android version📡 Detection & Monitoring
Log Indicators:
- Unusual Bluetooth pairing attempts from unknown devices
- Bluetooth stack crashes or memory corruption errors in system logs
Network Indicators:
- Unexpected Bluetooth connections from suspicious devices
- Abnormal Bluetooth protocol traffic patterns
SIEM Query:
source="android_system" ("bluetooth" AND ("crash" OR "memory" OR "corruption" OR "privilege"))